In large concrete structures, such as water storage tanks, the vertical walls can be constructed separately from the floor. An issue to be addressed with such structures is the tendency to leak through unintended voids created between the bottom of the walls and the floor. In some instances, this leakage can be inhibited by utilizing waterstops that are intended to provide a seal between the wall and the floor.
A waterstop is a flexible waterproof material placed at a joint between the concrete wall and floor to prevent the passage of water. Joints in concrete structures that are subject to a hydrostatic load are typically constructed with waterstops bridging the joints. In concrete joints subject to expansion and contraction, the waterstop is preferably designed to accommodate itself to movement. Typical applications for waterstops include large industrial tanks, sewage plants, water filtration plants, reservoirs, swimming pools, roofs, dams, foundations, retaining walls, and any concrete structure requiring watertight joints.
Waterstop systems are utilized particularly in the concrete tank construction industry to prevent the tank contents, such as water, from penetrating through the joints at the base of the tank where the walls meet the floor. Normally, waterstop systems are anchored directly into the concrete or adhered or fastened directly to the surface of the concrete. This configuration can inhibit access to the waterstop and joint for inspection and repair. Known waterstop systems are designed in recognition of the fact that concrete structures can experience significant movement at the joints, for example, the joint between the bottom edge of an upright wall and the floor, in response to changes in liquid level, climatic cycles, environmental changes, and the like. Consequently, waterstop systems are commonly made from various types of plastic and rubber because of their durability and flexibility.
Another product that is often employed with concrete structures is bearing pads. Bearing pads are used in the joint between two concrete structures to transfer load and movement from one structure to another. For example, bearing pads are often utilized between large concrete structures, such as between the vertical I-beams and horizontal slab surfaces of bridges. They can also compensate for irregularities in between surfaces and reduce wear and spalling that can occur between concrete or other types of structures. Bearing pads also act as a safety mechanism by providing flexibility in joints to inhibit damage from flexing or bending and absorbing and dissipating loads.
Typically, depending upon the type of concrete structures and use, either a waterstop or a bearing pad is utilized in a joint. Thus, to make a joint between two concrete sections both flexible and waterproof requires positioning two separate devices. In some cases, however, only one device can be used. There is a need in the industry for a device that can provide features of both a waterstop and a bearing pad, such that a single device can meet the needs for both.